This invention relates to tufting machines and more particularly to apparatus for monitoring the significant parameters of a tufting machine for reducing initial set-up times to obtain product specifications and for returning the machine to performance conditions which maintain these specifications.
Tufting machines of the broadloom type may run one particular carpet style for a period of weeks before the run is terminated and the machine is set-up for another style. Since these machines have a large number of pulleys and belts for driving the main shaft, the yarn feed mechanism and the backing feed mechanism, changes in the product occur during a long production run due to the normal wear, slippage and stretching of the belts and loosening of the pulleys. These changes occur gradually and are normally unnoticed by the operators until the product is far beyond specification.
In many instances after a carpet run is changed and a different style is run, it becomes necessary to change back to produce an additional run of the original style. This entails a resetting up of the machine to produce the original specifications of the carpet. When carpet produced by different runs are compared the results can be strikingly different. The operators first set the machine to where they believe the runs are compatable, carpet is run and compared. Readjustments are made and again compared. This trial and error set up can be quite expensive and rarely is the machine set so as to produce a run completely compatable with the original run.
The paraters controlled by the tufting machine, aside from the pattern itself, which affect the specification of the carpet are the pile height and the number of stitches tufted into the backing per inch thereof, which together with the gauge and the type of yarn and the backing material determine the density of the carpet. The pile height is determined by the position of the loopers below the bedplate and the amount of yarn fed to the needles per stitch. The number of stitches tufted per inch depends on the stitching speed and the fabric feed. Backing fabric tension may also affect the stitches per inch. The operators therefore have a number of variables to adjust in order to try to meet the original carpet specification; hence, the difficulty in obtaining the specifications.